package com.hspedu.static_.main_;

public class FinalExercise01 {
    public static void main(String[] args) {

    }
}

class Circle{
    private double radius = 1;
    private final double PI;

    {
        PI = 3.14;
    }

    public Circle(double radius) {
        this.radius = radius;
//        PI = 3.14;
    }

    public double cal(){
        return radius * PI * radius;
    }
}